1. Field of the Invention
The present invention relates to a disc brake vibration estimation method and a disc brake vibration estimation device.
2. Description of Related Art
A disc brake generates braking torque by bringing a pad into contact with a rotating disc rotor with hydraulic pressure of a hydraulic pressure cylinder. In the disc brake, a vibration is caused by contact of the pad with the rotating disc rotor and results in resonance between the rotating disc rotor and the pad to cause “brake squeal”. Here, vibration modes of brake squeal are categorized into an in-plane vibration mode and an out-of-plane vibration. In the out-of-plane vibration mode, a friction surface of the disc rotor which the pad contacts vibrates in the same direction as the rotational direction. In the in-plane vibration mode, the friction surface of the disc rotor vibrates in the circumferential direction of the disc rotor.
A technology that estimates the brake squeal corresponding only to the out-of-plane vibration has been suggested mode. Further, a method has been suggested that estimates the characteristic frequency of the disc rotor focusing on the in-plane vibration mode (Japanese Patent Application Publication No. 2004-19715 (JP 2004-19715 A)).
As described above, because the in-plane vibration mode is a factor constituting the brake squeal, it is demanded to estimate the vibration of the disc brake in the in-plane vibration mode. Further, if vibrations of the disc brake in both of the out-of-plane vibration mode and the in-plane vibration mode can be estimated, a model of the disc brake is created, and the brake squeal can be estimated through simulation, thus enabling design of the disc brake that reduces the brake squeal.